1. Field of the Invention
This invention relates to downhole motors or other downhole driving means for drill bits.
2. Prior Art
Present directional drilling systems when used for drilling of horizontal holes or angle holes from a vertical well can only deviate from the vertical a few degrees per hundred feet and to drill a curved hole from the vertical to a horizontal position requires the radius of bend of the curved hole to be several hundred feet. This means that a considerable amount of formation in the immediate vicinity of the vertical well hole is not affected by directional drilling. The use of downhole motors has reduced the radius of bend of a curved hole from the vertical to the horizontal but they are not as effective as they should be because of their long length which restricts their uses around curved holes with small radius of bends. So a flexible drive system is needed that can operate a drill bit in the drilling of a curved hole with a small radius of bend.
Downhole motors have to be very long in length to develop the horse power required to drive a drill bit because they can only be a few inches in diameter. Also present downhole motors can only operate in curved holes with a radius of bend much greater than the length of the motor, whereas the downhole flexible drive system will be able to operate in curved holes with radius of bends equal to or less than the length of the downhole flexible drive system.